the oil filter, thus eliminating the source of the problem.
B -- REPLACE ECM See: Powertrain Management/Computers and Control Systems/Engine Control Module/Service and
Repair/Removal
A -- END
Up to 08/2009
2GR-FE ENGINE CONTROL: SFI SYSTEM: P011B: Engine Coolant Temperature / Intake Air Temperature Correlation
P011B - Engine Coolant Temperature / Intake Air Temperature Correlation
DESCRIPTION
The engine has 2 temperature sensors, an engine coolant temperature sensor and an intake air temperature sensor, to detect the temperature while the
engine is operating. A thermistor, whose resistance value varies according to the temperature, is built into each sensor. When the temperature is low,
the resistance of the thermistor increases. When the temperature is high, the resistance drops. These variations in resistance are transmitted to the
ECM as voltage changes. Based on these temperature signals output from the sensors, the ECM determines the fuel injection duration and the
ignition timing to control the engine.
HINT
- Waiting is required to prevent the temperature of the engine from affecting the readings. If the engine has been operated
recently, it will not be possible to accurately compare the readings.
- For diagnosis, in order to duplicate the detection conditions of the DTC, it is necessary to park the vehicle for 7 hours. Parking
the vehicle for 7 hours ensures that the actual temperature of the engine coolant temperature and intake air temperature are
very similar. When the vehicle has been parked for less than 7 hours, differences in the readings may exist. This does not
necessarily indicate a fault.
MONITOR DESCRIPTION
The ECM monitors the difference between the engine coolant temperature and the intake air temperature when the engine is started cold to detect the
engine temperature conditions accurately. The monitor runs when the engine started cold after 7 hours or more has elapsed since the engine was
stopped (engine switch turned to off) on the previous trip. If the difference between the engine coolant temperature and the intake air temperature on
a cold start exceeds 20锟斤拷C (36锟斤拷F), the ECM interprets this as a malfunction in the engine coolant temperature sensor circuit and intake air temperature
sensor circuit, and sets the DTC.
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